Scientific Forecaster Discussion
fxus61 kctp 211154
Area forecast discussion
National Weather Service State College PA
754 am EDT Thu Jun 21 2018
low pressure, located over Maryland early this morning, will
track off the coast later today, as high pressure noses south
from New York state. Another low pressure system will track
northeast across the eastern Great Lakes Friday and Saturday,
with a trailing cold front coming through Pennsylvania Sunday.
Near term /through tonight/...
shortwave diving southeast across upstate New York is supporting
scattered lingering showers in high-precipitable water air mass across central
PA early this morning. Near term models indicate the best chance
of showers will shift into the southeast portion of the forecast
area by 7 am, mirroring progression of large scale forcing
ahead of shortwave.
Clearing skies, light wind and wet ground is already resulting
in patchy fog across the southern tier of New York state, and expect a
similar scenario to play out around dawn across the northern
tier of PA.
Temps are on track to bottom this morning from the mid 50s over
the northern tier, to the mid and upper 60s over the southeast
Short term /Friday/...
a much drier northerly flow will overspread PA later today, as
shortwave and associated surface low over southern New Jersey push off
the coast. Model soundings support clearing skies from north to
south during the morning and early afternoon. Will maintain low
pops across Somerset and southern Bedford counties, where enough
low level moisture will remain to perhaps support a diurnally-
driven afternoon shower. Otherwise, expect a dry late morning
and afternoon across the rest of the region. Model 850mb temps
near 14c should translate to Max temps from the upper 70s over
the high terrain of the Appalachians, to the low and mid 80s in
An approaching warm front over the Ohio Valley will spread
increasing cloudiness over the region tonight, with scattered
showers moving into the southwest portion of the forecast area.
A tight pressure gradient between high pressure east of New
England and low pressure over the Midwest will result in a
moist, southeasterly low level jet focused over southwest PA
early Friday, likely resulting in a wet start to the day across
The Laurels and south central mountains. Gefs indicates this
anomalous southeasterly low level jet and plume of higher precipitable waters
will lift slowly northeast Friday, resulting in an good chance
of rain across all but the extreme eastern portion of the
forecast area by late in the day.
Cloud cover, rainfall and easterly flow north of warm front will
result in a cool day for June with readings likely stuck in the
60s across the central mountains and only reaching the low 70s
over the susq valley.
Long term /Friday night through Wednesday/...
upper low over the Midwest will lift northeast across the
eastern grt lks Friday night and Saturday. Overrunning rain
appears likely Friday night into Saturday morning, as the region
remains north of the warm front. Significant model disagreement
Saturday PM, with Canadian/NAM keeping warm front hung up west
of the alleghenies, while ec/GFS push warm front through during
the afternoon. Have leaned a bit cooler than guidance, but
plenty of uncertainty with regard to late day Max temps. In
either case, potent large scale forcing and a surge of anomalous
precipitable waters ahead of upper trough point toward a wet day.
A trailing cold front is progged to come through Sunday,
accompanied by a chance of showers/tstorms. Heights rise early
next week and a much more summerlike weather pattern is expected
by the middle of next week and later.
Aviation /12z Thursday through Monday/...
a drier, northerly flow will spell improving conditions from
north to south by Thursday afternoon. Restrictions will linger
the longest over the southwest terminals. Showers and sub-VFR
conditions will spread back into the airspace from southwest to
northeast Friday into Friday night.
Fri...showers and MVFR-IFR cigs spreading southwest-northeast
through Friday night.
Sat...am MVFR-IFR cigs gradually improving Saturday afternoon.
Scattered to numerous showers; isolated ts possible SW 1/4.
Sun...scattered showers/isolated thunderstorms.
Mon...no sig wx.
astronomical Summer (june solstice) begins at 6:07am. Today
Marks the longest day and shortest night in the northern
hemisphere, and the exact moment when the sun's rays reach as
far north as they get during the year, appearing straight
overhead along the Tropic of cancer, at 23.5 degrees north
latitude. As a result, the sun will take its highest and
longest path through the sky.
For State College, sunrise will occur at 5:40am with
sunset at 8:46pm. The total daylength is 15 hours, 6 minutes and